NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: nht95-3.20OpenTYPE: INTERPRETATION-NHTSA DATE: June 18, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: The Honorable Ken Calvert -- Member, United States House of Representatives TITLE: NONE ATTACHMT: ATTACHED TO 3/27/95 LETTER FROM KEN CALVERT TO EDWARD D. HARRILL TEXT: Dear Mr. Calvert: Thank you for your letter on behalf of your constituent, Mr. Alexander H. Patnode of Lake Elsinore, concerning an engine stand your constituent purchased from Pep Boys. Mr. Patnode asked for assistance after the engine stand caused the engine to fall, i njuring his ankle. As explained below, the National Highway Traffic Safety Administration (NHTSA) considers the engine stand to be "motor vehicle equipment," subject to our regulation. NHTSA has authority to issue Federal motor vehicle safety standards for new motor vehic les and new items of motor vehicle equipment. 49 U.S.C. section 30102(a)(7) defines "motor vehicle equipment" in relevant part as: (A) any system, part, or component of a motor vehicle as originally manufactured; (B) any similar part or component manufactured or sold for replacement or improvement of a system, part or component, or as an accessory, or addition to a motor vehicle . . . (emphasis added) Although an engine stand is not a system, part, or component of a motor vehicle, it would be considered an "accessory" to a motor vehicle. NHTSA has typically used two criteria in determining whether a product is an "accessory." The first criterion is w hether a substantial portion of the expected use of the item is related to the operation or maintenance of motor vehicles. Expected use is determined by considering product advertising, product labeling, the type of store that sells the equipment, and i nformation about how the product is used. The second criterion is whether the product is intended to be purchased or otherwise acquired, and principally used by, ordinary users of motor vehicles. If a product satisfies both criteria, it is deemed an "acc essory." We have determined the engine stand is an accessory, and thus an item of motor vehicle equipment. Applying the two criteria to the engine stand, (1) the engine stand is intended to be used in the maintenance of motor vehicle engines, and (2) assuming th e stand was new when sold to Mr. Patnode, it was intended to be acquired and used by ordinary users of motor vehicles. We have searched our files by computer for reported complaints about engine stands, and for manufacturers' service bulletins and recalls. The search was conducted according to manufacturer (Rally) and equipment type (motor vehicle equipment: jacks, and other). A summary of the search results is enclosed. We found no reported instance of an injury caused by an engine stand, or of a manufacturer's issuing a service bulletin or recall because of an engine stand problem. We will keep a copy of Mr. Patnode's letter in our files on reported complaints. In the future, the letter may be helpful in establishing a pattern of safety-related concerns caused by the type of engine stand that resulted in Mr. Patnode's injury. I hope this information is helpful. If there are any questions, please let me know. |
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ID: nht95-3.40OpenTYPE: INTERPRETATION-NHTSA DATE: July 10, 1995 FROM: Ricardo Martinez -- M.D., NHTSA TO: Shih-Chiang Chen -- President, Top World Traffic Equipments Co., Ltd. TITLE: NONE ATTACHMT: ATTACHED TO 6/15/95 LETTER FROM SHIN-CHIANG CHEN TO DOT MINISTER TEXT: Dear Sir: This is in reply to your letter of June 15, 1995, to the Department of Transportation regarding your invention, the "brake condition warning sensor." You ask whether such an invention is permissible in this country. The sensor causes flashing in "the third brake light" keyed to the rate of deceleration. Under the Federal regulations in the United States, motor vehicles must be manufactured so that the third brake light (or "center highmounted stop lamp" as we call it) and all other stop lamps are steady-burning when they are in use. After the vehicle is sold, Federal law prohibits any manufacturer, dealer, distributor, or motor vehicle repair business from installing the sensor to modify the performance of the third brake light and cause it to flash. However, Federal law does not prohibit the owner of the car from installing the sensor. In this circumstance, the law of the State in which the vehicle is operated must be consulted to determine whether a flashing third brake light is permissible. We a re not able to answer questions about State laws. If you wish an opinion on State laws governing flashing third brake lights, you should write the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If I can be of further assistance, please contact me or Mr. John Womack Acting Chief Counsel (202) 366-9511. |
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ID: nht95-5.19OpenTYPE: INTERPRETATION-NHTSA DATE: July 10, 1995 FROM: Ricardo Martinez -- M.D., NHTSA TO: Shih-Chiang Chen -- President, Top World Traffic Equipments Co., Ltd. TITLE: NONE ATTACHMT: ATTACHED TO 6/15/95 LETTER FROM SHIN-CHIANG CHEN TO DOT MINISTER TEXT: Dear Sir: This is in reply to your letter of June 15, 1995, to the Department of Transportation regarding your invention, the "brake condition warning sensor." You ask whether such an invention is permissible in this country. The sensor causes flashing in "the third brake light" keyed to the rate of deceleration. Under the Federal regulations in the United States, motor vehicles must be manufactured so that the third brake light (or "center highmounted stop lamp" as we call it) and all other stop lamps are steady-burning when they are in use. After the vehicle is sold, Federal law prohibits any manufacturer, dealer, distributor, or motor vehicle repair business from installing the sensor to modify the performance of the third brake light and cause it to flash. However, Federal law does not prohibit the owner of the car from installing the sensor. In this circumstance, the law of the State in which the vehicle is operated must be consulted to determine whether a flashing third brake light is permissible. We are not able to answer questions about State laws. If you wish an opinion on State laws governing flashing third brake lights, you should write the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If I can be of further assistance, please contact me or Mr. John Womack Acting Chief Counsel (202) 366-9511. |
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ID: nht94-7.47OpenDATE: March 10, 1994 FROM: Norman Duncan -- President, Study-Tech, Inc. TO: Rodney Slater -- Administrator, FHA Transportation Department TITLE: None ATTACHMT: Attached to letter dated 5/18/94 from John Womack to Norman Duncan (A42; VSA 108(a)(2)(A); Std. 108) and letter dated 10/22/93 from John Womack to Thomas G. Cehelnik TEXT: The purpose of this letter is to request from your office AN INTERPRETATION OF THE EXISTING VEHICLE CODE as it may apply to a safety-warning system that our corporation has devised. The system: - Is designed to operate at the rear of vehicles to warn the cars following that they are slowing down. - Can be attached to either the existing brake lights of the vehicle, or could use separately mounted "warning lights" mounted at the rear- deck level and facing toward the back of the vehicle. - Will automatically be activated the moment the vehicle "begins to slow-down" due to deceleration. There are many benefits to be derived from the use of this device. For example: - There are critical time intervals between when a driver notes an emergency ahead and when the driver reacts. Precious seconds are lost before the driver's reflex action activates the brake lights. (Note: Using the "Early-Warning Slow-Down Safety Light", the driver following would see the warning light at the precise moment that the vehicle begins to slow.) According to statistics gathered from several state's traffic and crash facts books, (Eg. "Illinois Crash Facts and Statistics - 1992), about 25% of all collisions involving two vehicles are rear-end type accidents. This is an alarming fact! This type of accident is in the category of "Could-be-Avoided" if drivers were more alert, or a warning signal was given at the moment of deceleration of the vehicle in front. That degree of being "alert" in normal traffic is the foundation for our "Early-Warning Slow-Down Safety Light". We envision this device to be the latest in an emerging field of new safety devices. The newest safety devices include: the air bags, the rear-deck additional "stop light", improved head lamps and Anti-locking Brake Systems. Soon, we understand, General Motors will install running lights for their cars that will be "on" whenever the ignition is turned on. All of these recently developed safety features are designed to bring about higher standards for safety for our nation's highways. Our device, we feel, is another important extension of this concern to make our U.S. vehicles as safe as possible. We need your assistance and look forward to your answers to the following questions: A. Can current vehicle codes be interpreted to allow for an automatic signal when a vehicle begins to slow-down? B. If vehicle codes do not allow for this type of device, would you or some member of your staff be willing to assist us in an effort to develop plans to allow this type of device? C. Would you or members of your staff be interested in attending a demonstration of the prototype of the safety device? (To be arranged.) It is our goal to apply for a patent for this device because it represents important "new" technology in this particular field. An early response from your office would be appreciated very much. We look forward to hearing from you. |
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ID: 3236yyOpen Mr. D. E. Graham Dear Mr. Graham: This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 118 Power Windows (49 CFR 571.118). As you noted in your letter, the agency published a final rule amending Standard No. 118 in the April 16, 1991, edition of the Federal Register (56 FR 15290). You requested clarification of certain requirements in that final rule. The agency has received several petitions for reconsideration of the final rule amending Standard No. 118. The agency is currently reviewing the merits of each petition. The agency will issue a notice in the Federal Register granting and/or denying the petitions. In that notice, the agency will also address the concerns raised in your request for an interpretation on Standard No. 118. Please let us know if you have any questions about the issues raised in your letter after our response to the petitions for reconsideration has been published and you have had the opportunity to review it. If you need more information on this subject, please feel free to contact Dorothy Nakama of my staff at this address, or by telephone at (202) 366-2992. Sincerely,
Paul Jackson Rice Chief Counsel /ref:118 d:ll/20/9l |
1970 |
ID: nht78-3.7OpenDATE: 01/26/78 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Oklahoma Department of Public Safety TITLE: FMVSS INTERPRETATION TEXT: This responds to your letter of December 9, 1977, asking whether the recent amendment of Safety Standard No. 205, Glazing Materials, permits the use of plastic glazing in school buses. The answer to your question is yes. Safety Standard No. 205, as amended December 5, 1977 (42 FR 61465), allows the use of rigid plastic glazing in doors and windows of all buses, including school buses. Please note, however, that plastics cannot be used for bus windshields or in doors or windows to the immediate right or left of the driver. Sincerely, ATTACH. Oklahoma Department of Public Safety December 9, 1977 Hugh Oates -- National Highway Traffic Safety Administration Dear Mr. Oates: RE: Motor Vehicle Safety Standard #205 as amended by the Federal Register Docket #71-1, Notice #6, published 12-5-77 On December 5, 1977, a notice was published in the Federal Register amending Motor Vehicle Safety Standard #205, glazing material, which added to the list specified in ANS Z26, items 4 and 5 allowing the use of plastics in the side windows of buses. My question is, does this also include the use of items 4 and 5 of the ANS Z26 Standard in school buses. Sincerely, Joe Wall, Asst. Director -- Vehicle Inspection Division |
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ID: nht94-4.17OpenTYPE: INTERPRETATION-NHTSA DATE: August 31, 1994 FROM: Harold Sousa TO: Counsel, NHTSA TITLE: NONE ATTACHMT: Attached to 1/4/95 letter from Philip R. Recht to Harold Sousa (A43; Std. 121; Part 551) TEXT: I represent a factory in Brazil that manufactures special product that prevents the air from escaping from the tires of trucks and buses. In addition, the product keeps the pressure in the tire in the case of a puncture. This system uses air from the brake system of the vehicle if there is a hole in the tire, air will be supplied until the driver finds a place to repair or change the tire. Several companies in Brazil have been using the air-system like an insurance requirement which avoids problems like: * stopping on a highway or anywhere to change the tire therefore loosing time, * if one of the double back tires is damaged, the system supplies air that won't overload the other tire, avoiding an explosion of the good tire. I'm explaining this product because I would like to import this system from Brazil to the U.S.A. And I have to be sure that I am not breaking the laws of this country I included a copy of this procedure installed in a wheel. I hope to hear from you soon, Enclosure (Photo omitted.) |
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ID: nht91-7.15OpenDATE: November 20, 1991 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: D. E. Graham -- Engineering Manager, Regulatory, Test & Service Engineering, ASC Incorporated TITLE: None ATTACHMT: Attached to letter dated 10-16-91 from D. E. Graham to Richard Reed (OCC 6591) TEXT: This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 118 Power Windows (49 CFR S571.118). As you noted in your letter, the agency published a final rule amending Standard No. 113 in the April 16, 1991, edition of the Federal Register (56 FR 15290). You requested clarification of certain requirements in that final rule. The agency has received several petitions for reconsideration of the final rule amending Standard No. 118. The agency is currently reviewing the merits of each petition. The agency will issue a notice in the Federal Register granting and/or denying the petitions. In that notice, the agency will also address the concerns raised in your request for an interpretation on Standard No. 118. Please let us know if you have any questions about the issues raised in your letter after our response to the petitions for reconsideration has been published and you have had the opportunity to review it. If you need more information on this subject, please feel free to contact Dorothy Nakama of my staff at this address, or by telephone at (202) 366-2992. |
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ID: nht76-2.35OpenDATE: 06/02/76 FROM: AUTHOR UNAVAILABLE; S. P. Wood; NHTSA TO: Stanley Electric Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of April 20, 1976, asking for an amendment of S4.1.1.21 of Motor Vehicle Safety Standard No. 108 to allow a plus tolerance of 7.5 percent on maximum wattage requirements for Type 1A and 2A headlamps. I enclose a copy of an interpretation furnished the General Electric Company which states that such a tolerance is allowed. However, to clarify our intent we plan to amend Standard No. 108 in the near future in the manner that you suggest. YOURS TRULY, STANLEY ELECTRIC CO., LTD. April 20, 1976 Att.: E. T. Driver Director, Office of Crash Avoidance Motor Vehicle Programs U.S. Department of Transportation National Highway Traffic Safety Administration In item (c) of S4.1.1.33, FMVSS No.108 (41F.R. 1483 - January 8, 1976), a tolerance of +7.5% is allowed to the maximum wattage of each circular unit of automotive headlamps. On the other hand, in item (b) of S4.1.1.21, FMVSS No.108 (40F.R. 54426 - November 24, 1975), such tolerance is not clearly specified for rectangular units. From the table 3, SAE J573f, however, in case of these rectangular units, we noted, by calculation based on the maximum amperages specified there, that almost the same tolerances are allowed to the maximum wattages as those allowed by S4.1.1.33, FMVSS No.108. Therefore, we would like to interprete the provision regarding the maximum wattages of rectangular units as that the same tolerance of +7.5% is also being allowed by you. Your comments on this matter is requested. Furthermore, if such interpretation is not accepted by you, we ask you to amend the provision of S4.1.1.21 so that the same tolerance of +7.5% which is now being allowed for circular units may also be allowed to the maximum wattages of type 1A and type 2A rectangular units. Thanking you in advance for your cooperation, T. Takeda Manager, Automotive Lighting Engineering Dept. |
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ID: 9711Open Mr. Shih-Chiang Chen Dear Sir: This is in reply to your letter of June 15, 1995, to the Department of Transportation regarding your invention, the "brake condition warning sensor." You ask whether such an invention is permissible in this country. The sensor causes flashing in "the third brake light" keyed to the rate of deceleration. Under the Federal regulations in the United States, motor vehicles must be manufactured so that the third brake light (or "center highmounted stop lamp" as we call it) and all other stop lamps are steady-burning when they are in use. After the vehicle is sold, Federal law prohibits any manufacturer, dealer, distributor, or motor vehicle repair business from installing the sensor to modify the performance of the third brake light and cause it to flash. However, Federal law does not prohibit the owner of the car from installing the sensor. In this circumstance, the law of the State in which the vehicle is operated must be consulted to determine whether a flashing third brake light is permissible. We are not able to answer questions about State laws. If you wish an opinion on State laws governing flashing third brake lights, you should write the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If I can be of further assistance, please contact me or Mr. John Womack Acting Chief Counsel (202) 366-9511. Sincerely, Ricardo Martinez, M.D. ref:108 d:7/19/95
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1995 |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.